Digester



- 2 Sheets-Sheet 1.

J. HESS.

DIGESTER.

(No Model.)

Patented Aug. 12, 189.0

wit names (No Model.) 2 Sheets-Sheet 2. J. HESS.

- DIGBSTER.

No. 434,272 Patented Aug. 12, 1890.

WITNESSES:

A HOME).

NlTED STATES .ATENT Fries.

JULIUS HESS, OF PORT HURON, MICHIGAN.

DIGESTER.

SPECIFICATION forming part of Letters Patent No. 434,272, dated August 12, 1890.

Application filed December 19, 1889- Serial No. 334,255. (No model.)

To all whom, it may concern.-

Be it known that I, JULIUS HESS, a citizen of the United States, residing at Port Huron, county of St. Clair, State of Michigan, have invented certain new and useful Improvements in Digesters, of which the following is so full, clear, and exact a description as will enable others skilled in the art to which my invention appertains to make and use the same, reference being had to the accompanying drawings, in wl1ich Figure 1 is a perspective view of the outside of my digester.

pulp for paper and other purposes from wood (the wood to be boiled or steamed in chemicals and acid within the digester) by the wellknown bisulphite process, and one which will resist the action of the acid, the tendency of which is to eat through the digester and also to burst the digester by reason of the great pressure superinduced by the action of the heat, the weight of the material in the digester, and the action of the chemicals during the process of digestion.

The objects generally of this invention are to obviate these defects and disadvantages; and the invention consists in the novel construction, arrangement, and combination of parts, as will be hereinafter fully explained, and particularly pointed out in the claims at the end of the specification.

In the accompanying drawings, A designates the inner lining of my digester, which is to be made of bricks which areacid-proof and made of porcelain or other suitable clays, or of glass laid in cement or other impervious filling. The lower portion of th'einterior of the digester is provided with a step B, which serves to support a coil of lead pipes B for heating the contents of the digester with steam. Next to the inner casing A is the lining O, which is made of vapor, steam, and water-tight material, such as lead, asphaltum, &c. This lining is to be continuous and solid throughout, and on the outside of this lining O is an outer main brick casing D, laid in cement with water-tight joints, and made somewhat thicker than the inner lining or wall A of the digester. On the outside the digester is provided with a multiplicity of iron hoops E E, made of strong T orother suitable shaped iron, and each hoop at the joints to be firmly bolted together.

The bottom of the digester is provided with a large iron plate I upon which rests the main structure of the digester. The plate F is provided with a central opening G, forming a man-hole through the bottom of the digester, which is covered by an iron head II, which is held in placeby the pivotal bolts a a, which are in turn secured to the ring or band I, which extends around the opening G, as shown in Fig. 2. The outer portion of the plate F is provided with perforations b I), through which pass longitudinal vertical rods J J, and which are also extended through the perforations e e in the periphery of the top outer plate K, which is also provided with a supplemental ring or collar L, extending around the opening M, forming a manhole in the top of the digester, which is also covered by an iron plate N, and which is held in place by suitable bolts a a. I The longitudinal ver tical rods J J are provided with suitable heads and nuts to hold the plates firmly against movement away fr m each other. The lower inner portion of the digester is provided with a supplemental secli )n of lead or other acidproof material forming lining 0, which prevents the penetration ofthe acids at this point. Owing to the immediate presence of intense heat and the great weight of the liquid this additional supplemental lining is of prime importance in this position.

From the foregoing it will be seen at a glance that a digester made in accordance with my 0 invention will be durable and will readily withstand the pressure of liquids and gases within the digester during process of digestion, and the material of which the digester is made will-be easily obtained in any part of 5 the country, or those parts of it which are not at hand can be quickly and easily shipped to the point where the plant is to be erected and without any great expense oftime or the necessity of establishing a machine-shop for the purpose of putting the digester together where it is to be used.

The digesters of today, which are made of heavy platesof iron or bronze bolted together,

are the source of great trouble and expense in their original construction. It is necessary to establish a boiler-manufactory at the plant where the digester is to be erected, and this alone is an expense sufficient to construct a digester of considerable size and value. It will be understood that all iron which is likely to come into contact with the acid used should be covered over with an acid-proof lining.

A digester made in accordance with myinvention will be cheap compared with the cost of the ordinary digester, and the contraction and expansion of the materials of the digester will be so evenly counteracted that rupture and distortion will be entirely avoided. The contraction and expansion of the materials will be so gradual and will be distributed through so much material thatit will be practically imperceptible and will not injure the main structure. A supplemental vapor-proof lining P is also provided at the top curved portion of the main body of the digester. Owing to the shape of the digester at this point additional vapor-proof lining is of great importance. In some instances it may be found desirable to join the bands E all to gether in one continuous strip of metal and put them around the digester in the shape of a coil. This will give great length to the band itself,'and consequent ext-ended surface and material through which the force of contraction and expansion will be distributed, thus lessening the liability of rupture, and making greater provision for readjustment of the band when cooling and consequent contraction take place. This supplemental coil of metal band maybe put around the digester after the individual bands E have been adjusted to place, or it may be put on before they are adjusted, or, it may be used with or without them, as the case and circumstances may require.

I do not wish to be understood as limiting myself to the exact construction shown, nor to the proportions and contour of material and structure illustrated in the drawings, as the same may be varied somewhat to suit the circumstances without materially departing from the spirit of my invention and without in any way interfering with its usefulness.

Having now described the objects, uses, and advantages of my device, and having set forth in detail a means of constructing a digester in accordance with my invention, what I wish to secure by Letters Patent, and what I therefore claim, is

1. In a digester of the character described, a main inner acid-proof lining of bricks, in combination with an outside lining of vaporproof material and an outside easing of masonry, a top and bottom plate for the digester, and longitudinal external vertical rods extending 'from one plate to the other and holding the structure together, and a supplemental acid-proof strip, substantially as and for the purposes specified.

2. In a digester of the character described, the main structure provided with layers of acid-proof and vapor-proof material, respectively, the innerlower portion of the digester provided with a step and coils of lead pipe resting on said step within the digester, substantially as and for the purposes specified.

3. In a digester of the character described, the main structure of the digester, consisting of layers of acid-proof and vapor-proof material, respectively, the same provided at top and bottom with supplemental vapor-proof strips, and the entire structure re-enforced by metallic horizontal hoops and having a top and bottom plate secured in position with relation to each other and the digester by iongitudi nal vertical external rods, substantially as and for the purposes specified.

4. In a digester of the character described, an inner lining of acid-proof material provided with a step and a coil of lead pipes located on said step, an outer casing of vaporproof material, and a main structure of masonry outside of the vapor-proof layer, horizontal hoops made of T-irou surrounding and re-enforcing the main walls of the digester, a top and bottom perforated plate at each end of the digester, longitudinal vertical rods J, securing the platestogether, and additional supplemental strips of vapor-proof lining located at top and bottom of the digester, all constructed and combined to operate substantially as and for the purposes specified.

In testimony whereof I allix my signature in the presence of two witnesses.

JULI US HESS.

\Vitnesses:

JOHN Snonrna, DANIEL RYAN. 

